The present invention relates to a continuously variable transmission means for transmitting torque from a driving pulley to a driven pulley, each of pulleys having surfaces of a generally V-shaped cross-section.
Such a continuously variable transmission means is known in the form of a rubber V-belt which acts as a torque transmitting element. A rubber V-belt, however, has its restrictions as to the strength of the material employed. Such a transmission means with a V-belt extending between two pulleys enables control of the number of revolutions of the driven pulley to be effected, by varying the size of a V-shaped opening(s) in one or both of the pulleys or by varying the pressure with which the belt is forced into the opening. Thus, the position of the belt on the pulley and the effective diameter of the pulley can be varied and it is possible to vary the ratio of the input and output number of revolutions continuously.
It is also known to form a continuously variable transmission means from a predetermined number of metallic hoops, on which longitudinally shiftable V-shaped members are mounted, the members linking up and extending around the total circumference of the hoops. In this known construction, the flexible continuous member consists of a carrier which comprises a plurality of hoops superimposed with some clearances, the innermost one lying on a rounded topside of each of a plurality of V-shaped blocks made of metal, such as steel. Driving force is transmitted from the driving pulley to the driven pulley by the movement of V-shaped members. As the innermost metallic hoop has metal contact with the moving V-shaped blocks, the hoop is subjected to tensile force from the blocks when the blocks are shiftable. Disadvantages of this construction are that the innermost hoop is subjected to the biggest tensile stress in all the hoops.